Thomas is a two-time winner of the Vezina Trophy (2009 and 2011) as the NHL's best goaltender, and was a member of Team USA in the 2010 Winter Olympics in Vancouver.

Thomas is one of four American-born players to win the Conn Smythe Trophy, along with Brian Leetch, Jonathan Quick, and Patrick Kane.

[5] Thomas played four seasons (1993–97) of college hockey for the University of Vermont, posting an 81–43–15 record to go with a 2.70 GAA and .934 save percentage.

Thomas played 18 games with a save percentage of .947 as the team advanced through the playoffs to defeat Ilves in the finals and win the Finnish championship.

After signing with the Edmonton Oilers on June 4, 1998,[7] Thomas initially moved to the American Hockey League (AHL) the following season with the Hamilton Bulldogs, where he played 15 games, before again transferring to HIFK.

In 1999–2000, Thomas returned once again to North America to play for the Detroit Vipers of the IHL, then spent the next season with AIK IF of the Swedish Elitserien.

In 2001, he joined the Boston Bruins organization, but chose to continue playing in Europe, spending his first full SM-liiga season in 2001–02 with Kärpät.

He made his National Hockey League (NHL) debut with the Bruins during the 2002–03 season, appearing in four games total, with a .907 save percentage and a 3–1 record.

[7] As a result of the one-season duration NHL lockout in North America, in 2004–05 Thomas joined Jokerit of the SM-Liiga, his fourth stint in Finland.

In August 2005, Thomas signed to play with Jokerit for the 2005–06 season, but his contract included an NHL option and on September 14, one day before the regular season in the SM-liiga started, Thomas announced he had signed with the Boston Bruins, leaving Jokerit with rookie goaltender Joonas Hallikainen as their sole goaltender.

Eventually, Jokerit used three North American goaltenders (Karl Goehring, Steve Passmore and Tom Askey) that season, but missed the playoffs.

Although Boston's previous starter, Andrew Raycroft, was traded to the Toronto Maple Leafs in the 2006 off-season, Thomas began the 2006–07 season as the Bruins' backup, behind Hannu Toivonen instead.

[8] On July 1, 2007, the Bruins acquired goaltender Manny Fernandez from the Minnesota Wild and later traded Thomas' previous backup, Toivonen, to the St. Louis Blues.

[citation needed] However, as Fernandez went down to injury early in the season, Thomas seized the opportunity and once again emerged as the Bruins' starter.

[12] Two days later, on April 4, he posted his career-high fifth shutout of the season in a 1–0 win against the New York Rangers, clinching the top spot in the Eastern Conference, Boston's first title since 2001–02.

On June 18, Thomas was awarded the Vezina Trophy, edging Minnesota Wild netminder Niklas Bäckström and the Columbus Blue Jackets' rookie goaltender Steve Mason.

On May 27, 2011, Thomas posted a 1–0 shutout victory over the Tampa Bay Lightning in Game 7 of the Eastern Conference Finals, sending the Bruins to their first Stanley Cup appearance since 1990.

In the Finals, Thomas again posted a 4–0 shutout victory in Game 7 against the Presidents' Trophy-winning Vancouver Canucks to win the series 4–3 and the Bruins' first Stanley Cup title since 1972.

[19] Thomas has mentioned he chose 34 as his jersey number with the Panthers in honor of John Vanbiesbrouck, a goaltender from Michigan whom he grew up watching.

[citation needed] After graduating from the college program, Thomas was named to Team USA for the 1998 World Championships following his rookie professional season and played his first full international game.

He appeared in three games before suffering a groin injury, splitting starts with Robert Esche and posting a 1.50 GAA with one shutout against Latvia in the preliminaries.

[citation needed] On January 1, 2010, Thomas was selected to be a member of the United States men's hockey team for the 2010 Vancouver Olympics, serving as backup goaltender to the Buffalo Sabres' Ryan Miller.

[citation needed] On February 26, 2010, Thomas made his Olympic debut in the United States–Finland semi-final, entering the game with approximately 11:30 remaining in the third period and a 6–0 lead.

[28] After winning the Stanley Cup in 2011, Thomas skipped the traditional victors' meet-and-greet with President Barack Obama at the White House on January 23, 2012; he was the only active Bruin not to attend.